Needle saver stop motion



Dec. 8, 1953 A. CRAWFORD TAL 2,661,615 E NEEDLE SAVER STOP MOTION Filed Aug. 2, 1951 Patented Dec. 8, 1953 UNITED STATES rEENT OFFICE NEEDLE SAVER, STOP MOTION Application August 2, 1951, Serial No. 239,938

(Cl. (i6-157) 10 Claims. l

This invention relates to stop motions for knitting machines and more particularly to devices for detecting faulty needles and faulty needle function arising from defective or snarled threads. A device of this general character is disclosed in United States Patent No. 2,257,037 dated September 23, 1941, and the present invention involves an improvement over prior devices of this type.

Detectors of the type to which the invention relates are adapted primarily to detect broken or bent needles or snarls or bunches of thread on a needle resulting from improper functioning of the latter or from a knot or other defect in the knitting thread. Conventionally, the device includes a detector linger which is mounted for en gagement with a faulty or displaced needle or a snarled thread at a needle, the finger in turn controlling a spring loaded element which, when released as a result of displacement of the nger by contact with the needle or snarled thread, will trip the stop motion of the machine either mechanically or by electrical means to bring the operation of the machine to a halt. In devices of this character it is customary also to so mount the detector nger so that displacement thereof in the process of detecting will result in the finger being moved to a position remote to the needles.

A principal object of the present invention is to lprovide a detector device o this character characterized by extreme compactness of form and simplicity of mechanical structure and which, when mounted on the machine, will involve a practical minimum of obstruction to the normal machine structure and its operation.

The invention contemplates also the provision of a device of this character adapted for operation in knitting machines of the rib type employing two cooperative sets of needles operating respectively in vertical and horizontal planes.

The invention resides further in certain mechanical and structural details hereinafter described and illustrated in the attached drawings, wherein:

- Figure l is a fragmentary sectional View of a rib knitting machine showing a detector device made in accordance with the invention mounted on the dial cam plate with the detector linger in operative position with respect to the needles of both sets;

Figure 2 is a fragmentary front elevational view of the detector needle showing the lower portion of the detector device as a whole;

Figure 3 is an enlarged sectional view of the detector device;

Figure 4 is a fragmentary side elevational view, partly in section, showing details of the detector nger mounting; -Y

Figure 5 is a sectional View on the line 5 5, Figure 3;

Figure 6 is a fragmentary sectional View on the same line illustrating certain of the elements in an alternative operation of adjustment;

Figure '7 is a view in perspective of the lower portion of the detector device showing the detector finger in the normal operative position; and

Figure 8 is a similar view in perspective showing the detector linger in the released and retracted position.

In the drawings, reference numeral I indicates the needle cylinder of a rib knitting machine, this cylinder being provided with the conventional vertical grooves 2 in which the cylinder needles 3 are mounted for vertical reciprocation in the usual manner. The needle dial plate of the machine is indicated by the reference numeral 4, this plate being provided with the usual radial grooves 5 in which the dial needles li are slidably mounted for radial reciprocation by action of cams on the underside of a dial cam plate 1. As far as described, the machine is conventional, and its mode of operation will be readily understood by those familiar with the art. Threads conducted to the needles in the usual manner are worked by action of the needles into a circular fabric 8 which, as produced, passes inwardly of the cylinder I and between the upper end of the cylinder and the outer edge of the dial plate 4, as well illustrated in Figure 1.

The detector device comprises a cylindrical casing Il! which is supported in the present instance upon a bracket II attached to the top of the plate l, as shown in Figure l, so that the cylinder overhangs the edge of the plate. The casing contains and forms a bearing for a, cylindrical member I2, the lower end of which projects from the lower open end of the casing as indicated at I3. An integral stem I4 extends upwardly from the member I2 through a sleeve I5 which is press-fitted or otherwise secured in the casing Ill, and the upper end of the stem I4 is secured in a hollow cylindrical member I6 which ts within the upper end of the casing I and projects upwardly through the open top of the latter as indicated at I1. The upper end of this member I6 carries a knurled head I8 by means of which the composite rock shaft comprising the member I2 and its extension I4 and the member I5 may be rocked manually in the casing. It will be noted that a shoulder I9 on the stem i4 of the member i2 lies in proximity to the lower end of the sleeve I 5 and, by engagement with the latter, prevents upward movement of the rock shaft in the casing. Movement of the shaft in the other direction is prevented by engagement of the lower end of the member IS with the upper end of the sleeve i5.

A coil spring 2l surrounds the lower end of the sleeve I5 and the adjoining portion of the stem I4 and has one end attached at 22 to the said sleeve, the other end being attached at 23 to the stem I. This spring tends to retain the rock shaft in a predetermined angular position within the casing, as hereinafter described, `but permits angular displacement of the shaft from.

this position for a purpose also hereinafter set forth.

The lower end of the member I2 of the rock shaft is bifurcated, as illustrated at 2e, andpivotally supported within this bifurcation upon a pin 25 is a detector finger 2S. A. spring 2i supported on the pin 25, and having its ends attached respectively to the head 2S of the pin and to the nger exerts resilient pressure on the finger tending to retain it in an extended position in which the nger 23 is in substantial alignment with the axis of the rock shaft. rfhis position'of the finger can be obtained, however, only -`when the shaft has been rocked within the casing against the tension of the spring 2l to a Predetermined position, shown in Figs. 3 and 7, since in the other permissible shaft positions an arm 3i at the upper end of the finger will interfere with a cam surface 32 at the lower end of the casing,

as shown in Figure 8, and will hold the nger in a retracted inoperative position angularly disposed with respect to the shaft axis, as shown in Fig. -8.

When the finger is inthe extended'or operative position (see Figures l and 7) an offset extremity 33 of the arm 3i will engage in an aperture 313 in the side of the casing, the spring 2l Vacting to move the finger about its pivot pin 25 into the position wherein the extremity 3S occupies the said aperture. The interlocking action thus obtained between the finger and the casing prevents the spring 2i from turning the rock shaft in the return direction, so that the detector finger in effect is locked in the extended operative position. A slight pressure on the lower end of the finger 23, however, is sufficient to turn it on its pin 25 to an extent sufficient to withdraw the offset eX- tremity 33 of arm 3! from the aperture Sil, whereupon the rock shaft is free to turn under action ofthe spring .2 i. rllhe spring 2l will tend to maintain the finger 23 in the extended position in which, as previously set forth, it lies substantially in Aalignment, with the vrotary axis of the rock shaft, but movement of the finger with the shaft under action of the spring 2 l, as described above, will bring the inner end of the arm SI into `contact with the cam 32 which will then act to rock the finger about the pin 25 into the retracted angular position in which it is shown in Figure 8.

As shown in Figure 1, the casing il! is mounted in an upright position above the needles of the two sets so that the finger 25 when in the operative position will extend substantially vertically downward into operative relation to the needles. When the finger is tripped, as hereinafter more fullydescribed, to release the offset extremity 33 from the `aperture 3d, the resulting angular movement of the finger under action of the spring 2l and cam 32 will carry the nger to a position il- 4 lustrated in broken lines in Figure l wherein the finger is elevated above the plane of the dial needles 3 and outwardly beyond the cylinder needles 3.

To reset the linger in the operative position it is merely necessary to `rotate the :rock shaft against the pressure of the spring 2'I through the medium of the knurled head I8 at the top of the shaft, the spring 2l operating to return the finger to the normal operative position wherein it is interlo'cked Vwith the casing through the offset extremity 33 of the arm 3| and the aperture 34. In this resetting movement the arm 3| moves progressively along. the surface of the cam 32 until the offset A33 comes into registration with the aperture 34 into which it moves under action of the spring 21.

As illustrated in Figures 3, 5 and 6, the hollow member I6 of the rock shaft has a circumferentialrslot 36 into which projects the 4innerr end of a screw 37, this screw-being threaded into -a fer.- rule 33 on Vthe upper Vend yof .thevcasing I0. The ferrule is .electricallyinsulated from thecasing by an insulating sleeve 39. The screw 3l;forms a terminal for a wire 5I which constitutesa-part of the stop motion circuit of the knitting machine with which the detector device is associated. The screw 3i also passes through .an 'enlarged aperture `ft2 in the casing I and Vhas -no -direct contact with the latter. 'The slot 36 in its relation tothe screw 3i is best illustrated in Figures 5 and 6. It will be noted that when the Stinger 2E is in the operative position the composite rock shaft will occupy a position 'wherein 'the'nner projecting end of thescrew is spaced Vfrornthe ends of the slot as shown inrFigure 5.; but'when the shaft has been'movedfby the spring 2|,after tripping of the linger 26 as described above,'the opposite end i3 of the slot 36' will be broughtinto contact with 'the screw, as rshown in :Figure 6,' thereby electrically connecting theY wire L4I with the shaft and through the shaft with 'the :casing i0 which is grounded to complete vthe circuit. The screwv 3l thereby acts'as a'stop limiting the rocking movement of .the shaft, and .also forms with the end wall of the slot 38 a switch `which controls the stop motion "circuit and when closed will interrupt the operation of the knitting machine.

The operation of the detector finger. with.re speot to the needles will be'well understood by those familiar with .the art. As illustrated in Figure l, the tpof the needle Yoccupies a position immediately adjoining lthe lower edges ofthetda'l needles and the inner edges of the cylinder needles at the point' of stitch formation, so that when a knotV or slub causes `a 'thread accumula-Y tion on a needle of either ofthe sets suchaccumulation will necessarily project intothepath of travel of the tip 'of the detector finger. Similarly, any of the dial needles which from 'any cause occupiesan abn'ormalor displaced position will lie in the path `of the lower end of theidetector finger. For coaction of the cylinder needles the finger carries a transversely projecting pin is which extends outwardly across the cylinder defined by the needles, as clearly shown in Figure l, for engagement with any defective dial or defective cylinder needles which might occupy'an abnormal position. The movement of vthe detector device with the cam plate 'i is in the direction of the arrow in Figure 2 so that contact'of the lower end of the finger with a needle or thread accumulation will result in a tripping of the finger as described above and immediate retraction of the needle to the position clear of both the dial and cylinder needles.

The device is extremely compact and is designed to occupy a position above and in substantial alignment with the needles of the cylinder group with the detector finger normally in alignment with the axis of the rock shaft upon which it is supported. When tripped the finger will move in a path resultant from its simultaneous movements about the axes of the pin 25 and of the rock shaft to lift the finger above the dial needles and to shift the finger angularly outwardly to a position clear of the cylinder needles, this compound movement being effected by a simple angular movement of the rock shaft under action of the cam 32.

We claim:

1. In a detector device of the character described, the combination with an axially fixed rock shaft, of a detector finger pivotally mounted on the shaft for movement about an axis transversely disposed with respect to the shaft axis and between alternative positions in one of which the finger lies approximately parallel to the axis of the rock shaft and in the other of which the finger is angularly disposed with respect to said axis, and means responsive to movement of the rock shaft about its axis for effecting angular movement of the finger about its axis between said alternative positions.

2. A detector device according to claim 1 wherein the means for effecting angular movement of the finger comprises resilient means tending to move the finger about its axis in one direction and a cam for reversely moving the finger in opposition to the spring.

3. A detector device according to claim 2 wherein the resilient means tends to retain the finger in the position approximately parallel to the axis of the rock shaft, and the cam is relatively fixed in the path of the finger in its movement with the shaft so as to move the finger into the alternative position angularly disposed with respect to the shaft axis.

4. A detector device according to claim 3 including a latching means releasable by angular displacement of the finger about its pivotal axis for preventing angular movement of the rock shaft when the finger is in the position approximately parallel to the axis of the shaft, together with a second resilient means connected to the shaft and exerting pressure on the latter tending to effect said angular movement and operative when the latching means is released to rock the shaft and to thereby shift the finger to the a1- ternative position angularly disposed with respect to the shaft axis.

5. A detector device according to claim 4 wherein the latching means comprises an arm on the ng'er having an offset end for engagement in an CII aperture in the relatively fixed structure of the cam.

6. A detector device according to claim 1 wherein the finger is movable between an alternative extended position in which it is approximately parallel to the shaft axis and a retracted position angularly disposed with respect to the shaft axis, there being resilient means tending to retain the finger in the extended position, a second resilient means tending to turn the shaft so as to move the finger to the retracted position, and latching means releasable by movement of the finger about its pivot for releasably retaining the finger in extended position.

'7. A detector device according to claim 6 including electric switch means operatively associated with the shaft, said switch being closed only when the shaft occupies a position wherein the finger is retracted.

8. A detector device according to claim 1 iricluding a casing wherein the rock shaft is rotatably mounted, the means for effecting the angular movement of the finger comprising a cam on the casing located in the path of movement of the finger with the shaft.

9. In a detector device for knitting machines, a rock shaft and means for mounting said shaft in a position above and approximately parallel to needles of the said machine, a detector finger depending from the lower end of the shaft into proximity 'to the needles and pivotally supported on the shaft for movements between alternative operative and inoperative positions in the first of which the finger is approximately parallel to the shaft axis and in the second of which it is angularly disposed with respect to said axis, said shaft having corresponding positions of angular adjustment about its own axis, and a spring tending to rock the shaft into the position corresponding to the inoperative position of the finger, resilient latch means for retaining the finger in operative position releasable by angular displacement of the finger about its axis, and cam means operative by movement of the shaft by said spring for moving the finger into the inoperative position.

l0. A detector according to claim 9 wherein the finger has a transverse pin projecting across the line of needles.

ALFRED CRAWFORD. MICHAEL ANTONEVICH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,257,037 Crawford Sept. 23, 1941 2,339,442 Wachsman Jan. 18, 1944 2,432,954 Vossen Dec. 16, 1947 

